* On August 16th, I was having problems with not being able to forward attachments, and, as per forum guidance, I deleted my email account on the handheld and set it up again (resent service books, etc.)

* Things worked fine. September 20th, I restarted my phone (after an application update and possibly also a low memory event) and noticed all my received messages between August 16th and September 20th were missing. Sent messages were still there, as were text messages, as well as all received messages before August 16th (going back about 6 months or so).

* Messages are configured to stay "forever" on the handheld. I use Outlook for my email client on my desktop. I do NOT tick the option to leave the messages on my server in Outlook, however I only delete junk email in Outlook, everything else is stored in folders so it does not interfere with the Blackberry.

* Seems it was either a low-memory event or BB glitch that caused the messages to be "lost". Setting up (recreating) the email account on August 16th seems to have saved earlier messages from being lost which is interesting and may suggest a way to safeguard messages from being deleted in the future.

* The strangest part of all is that I tried restoring a recent backup made on September 15th (a week before the messages mysteriously vanished), and the messages did not come back on the handheld.

So basically my two questions are:

1) Why didnít the messages come back after I did the restore?

2) Is there a way to safeguard messages from being deleted in the future in case of a low memory event (aside from trying to prevent low memory events)? Or, put differently, any ideas why the emails before August 16th (the same day I recreated the email account) were protected?

Is it possible that Blackberry used to "store" messages somewhere on their server when they were retrieved on the handheld and have recently stopped doing that?

PS: I've never left the messages on the server in Outlook and despite this have never before (in the two years I've had my phone) experienced any issue with regard to vanishing emails on my handheld.

PPS: My BB is configured to use the IMAP version for my mail server. Seems to be the default, not sure if that could make a difference... I have read that it is "better" to use the IMAP version over POP3.

If your BlackBerry deleted those messages due to low internal memory, the deletion order might have been carried over to the server and Outlook. There is no way to recover them if they were deleted in this fashion.

RIM has not changed anything with regards to storing messages. RIM doesn't store the email, it only delivers them from the provider's email servers through their own servers. I personally use IMAP whenever available and I do leave copies on the server.

The only way to safeguard against a repeat deletion is to keep an eye on free memory and do a battery pull whenever it gets near 20MB. That should leave plenty of room for safety. You might want to take a look at your apps and try to see what is using up the internal memory. And quit (not just close) any app you're done with rather than allow it to idle in the background. Idling apps are a prime cause of memory leak.

But why weren't the messages recovered when I did a Device -> Restore in BlackBerry Desktop Software? Do I need to do anything special besides choosing "full backup" when I backup my BlackBerry on my desktop? I assumed when I choose that option, that all messages on the BlackBerry were backed up on my desktop, and when I did the Restore, I expected to see the messages back again, irregardless of anything the BlackBerry or Outlook had done to them. Am I not understanding how the Backup/Restore operations work or where these messages are pulled from after a Restore operation?

With regard to memory issues, the only thing I'm ever low on is Application Memory, currently only 35 MB free.

The memory usage for Options and Email Setup Application seem ridiculously high, any idea what could cause that?

BTW, I mentioned that earlier emails (from August 4th through August 16th) were still on the handheld, and I now know why. Upon further investigation, I noticed via the View Folder menu option of the messages menu that I have four inboxes. One inbox contains emails after August 16th, one inbox contains emails on and before August 16th, and the other two are empty. The reason for this is that I recreated my email account on August 16th. So the scope of whatever problem is plaguing my poor blackberry is limited to the active/newest inbox (from August 4th through August 16th).

Could the previous low memory event have had lingering effects even after doing a restore? I would doubt that. Could some third party app be interfering somehow? The installed apps never bother the BB before. Is there any kind of easy test I could do, maybe some kind of event log to diagnose the problem?

From what I have read, there's no way to "import all messages less than 6 months old from Outlook" to the handheld if you use Blackberry Internet Server, but what about third party apps? Anyway, my main concern is to stop new emails from being deleted.

PS: Is there any kind of mechanism I can implement on the BB so that if memory is ever dangerously low, the BlackBerry turns off instead of poofing my inbox?

There is no third-party app to force a restart when memory gets critically low. This must be done manually every time.

To rule out a faulty BlackBerry you should wipe it with JL_Commander and restore the operating system, using the latest version available for your model. Try running it without any third-party apps for a week or two and keep an eye on the free memory. If it holds, add apps back one by one. Wait a couple days between adding apps and again watch the memory. That's the only way to root out something like this.

I've been following memory usage since the second instance of vanishing emails and there has consistenly been 90.0 MB of free memory. But then again, none of my apps are open. I guess I'll try testing them out one by one to check for memory leaks.

I am using OS 6 and have about 15 apps installed excluding those that are bundled with the BB. Yes, the few pictures/music/ringtones I have are on the SD card.

Taking a look at memory usage from yesterday, one thing that stands out is that the BlackBerry OS had a max memory usage of 198 MB compared to it's current memory usage of 147 MB. Is it normal for the memory usage of the OS itself to increase like that?